Assuming ideal gas behaviour, the ratio of density of ammonia to that of hydrogen chloride at same temperature and pressure is : (Atomic wt. of Cl = 35.5 u)

At 300 K, the density of a certain gaseous molecule at 2 bar is double to that of dinitrogen (N₂ ) at 4 bar. The molar mass of gaseous molecule is :

Among the following, the incorrect statement is :

Initially, the root mean square (rms) velocity of N₂ molecules at certain temperature is $$u$$. If this temperature is doubled and all the nitrogen molecules dissociate into nitrogen atoms, then the new rms velocity will be :